Integrated circuits are typically formed of layers of electrically semiconducting materials, electrically insulating materials, and electrically conducting materials that are layered in a complex series of processes such as doping, deposition, and etching of the materials in progressive layers. Typically, the various circuit elements within the integrated circuit are electrically connected using layers of the electrically conductive material, such as metal. These layers of electrically conductive material are usually patterned into interconnects. Several layers of interconnects may be used in the fabrication of a completed integrated circuit. Typically, each level of interconnects in an integrated circuit runs primarily in either the X or Y direction to allow for the electrical connection of the transistors and the macro elements that form an integrated circuit.
Sometimes it is desirable for two or more elements disposed on an X direction interconnect level, for example, to be electrically connected in a Y direction. In this manner, an electrical connection can be made between two or more elements that are in close proximity to one another, without requiring the connection to be made on a different level of electrical interconnects, which may reduce the total number of interconnect layers. However, when such a transverse electrical connection is made, it typically requires that no other electrical connections can be made in the area of the transverse electrical connection. In other words, it is typically preferred that none of the electrical interconnections within a single layer cross, or the electrical interconnections create a mass of short circuited connections. Thus, the use of a short transverse electrical connection tends to reduce the density of the electrical interconnect layer in which it is used.
The macro elements within an integrated circuit, such as resistors, fuses, and capacitors, are also constructed utilizing electrically conductive materials and other materials. However, the electrical properties of the conductive materials used for the macro elements are somewhat different from the electrical properties of the conductive materials used for the electrical interconnect layers. For example, the bulk resistance of the electrically conductive material used to form the macro elements is often much greater than that which is desirable for use in the electrical interconnect layers. One reason for this is that many of the macro elements are designed to be resistive elements or are otherwise not designed to carry an appreciable amount current for any significant distance. However, the electrical interconnect layers, on the other hand, are primarily designed to carry an appreciable amount of current for a significant distance, and preferably without a significant voltage drop. Therefore, the desired electrical properties of the different electrically conductive materials used for the macro elements and the electrical interconnect layers tend to be mutually exclusive.
Therefore, what is needed is an improved method of manufacturing integrated circuits that generally increases the routing density of the interconnect layers and generally decreases the overall number of interconnect layers.